Standalone Aspire Dashboard doesn't work with MCP

[sander1095]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm trying to run the Aspire Dashboard locally with Docker Compose:

  aspire-dashboard:
    image: mcr.microsoft.com/dotnet/aspire-dashboard:latest
    container_name: aspire-dashboard
    ports:
      - 18888:18888
      - 4317:18889
    environment:
      - ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS=true
      - ASPIRE_DASHBOARD_TELEMETRY_OPTOUT=true

This shows me an MCP icon in the dashboard:

When added to vscode, the mcp.json is modified with:

"aspire-dashboard": {
    "type": "http"
}

But this server doesn't start, the error logs are:

2026-02-26 11:13:05.003 [info] Stopping server aspire-dashboard
2026-02-26 11:13:05.021 [info] Starting server aspire-dashboard
2026-02-26 11:13:05.021 [info] Connection state: Starting
2026-02-26 11:13:05.038 [info] Starting server from LocalProcess extension host
2026-02-26 11:13:05.038 [info] Connection state: Running
2026-02-26 11:13:05.048 [info] Connection state: Error Error sending message to file:///undefined: TypeError: fetch failed

The docs don't mention much about configuring MCP with STandalone ASpire Dashboard, so I am unsure what to do next.

Expected Behavior

MCP works with standalone aspire dashboard, or if that's not expected, documentation that says this is not supported (and the MCP icon removed)

Steps To Reproduce

Create docker compose with:

  aspire-dashboard:
    image: mcr.microsoft.com/dotnet/aspire-dashboard:latest
    container_name: aspire-dashboard
    ports:
      - 18888:18888
      - 4317:18889
    environment:
      - ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS=true
      - ASPIRE_DASHBOARD_TELEMETRY_OPTOUT=true

Run it with docker compose up

Open the dashboard, try to connect to MCP, see failure logs I posted.

Exceptions (if any)

No response

.NET Version info

No response

Anything else?

No response

[sander1095]

I tried running this now that 13.2 has been released but the latest docker image is 12 days old (older than 13.2). It still doesn't work